/Engine/Source/Runtime/MovieScene/Public/Evaluation/MovieSceneEvaluationField.h
One-shot entities are only ever alive for a single evaluation, regardless of the range within the field. This makes them ideal for events or triggers.
void AddOneShotEntity ( const [TRange](API\Runtime\Core\Math\TRange)< [FFrameNumber](API\Runtime\Core\Misc\FFrameNumber) > & OneShotRange, int32 LocalIndex, int32 InMetaDataIndex )